Grease-dampened pointer



Aug. 15, 1950 L. A. PAINE EIAL 2, 3

GREASE-DAIPENED POINTER Filed April 20, 1946 a! W R5: 26 f2 [av ls flfJana A. Road '3 14'' [new Mug??? Patented Aug. 15, 1950 GRBASE-DAMPENEDPOINTER InuisLPalneandBichardLRoad,

West Lafayette, Ind., assignors to Duncan Electric ManufactoringCompany, La Fayette, Ind., a corporation of Illinok Application April20, um, Serial No. scum Claims. (Cl. 118-129) In various instruments itis desirable to provide a pointer or other indicator which moves withgreat ease during the normal operation of the instrument but,nevertheless, resists movement due to vibrations and the like. Forexample, in maximum demand meters for indicating the maximum rate ofpower consumption in an electric circuit, the meter element directlycontrols an indicator which in turn pushes a freely pivotal indicatorwhich should move easily and not be subjected to displacement byvibrations or intentional jolts. It should move easily so that thepusher indicator can move it to the correct value without unnecessaryloss of power. It should resist displacement because it may be pushed toits maximum position early in the billing period. and may be subjectedto a great deal of vibration between that time and the time when themeter is read. Furthermore, there are unfortunately some dishonestpersons who might endeavor to find a particular way to jar the meterhousing in order to jar the maximum demand pointer to a lower reading.

At least one attempt has been made heretofore to meet the problem by agrease-dampened pointer, but that has not been wholly satisfactorybecause changes in viscosity of the grease used for dampening themovement or vibration of the indicator caused variations in theoperating characteristics and also necessitated an undesirable verticaldisposltion of the indicator shaft so that the grease would not run outwhen warm or moderately hot temperatures were encountered.

According to the present invention, the shaft is horizontally disposedand a grease is used which is of substantially constant viscositythroughout a wide range of temperatures, in-

cluding all temperatures encountered in service. so that it never flowsaway from its original and proper location.

Additional objects and advantages will be apparent from the followingdescription and from the drawings in which:

Figure l is a face view of a meter embodying the present invention; and

Fig. 2 is a fragmentary, vertical, sectional view taken approximately onthe line 2-2 of Fig. 1.

Although the law requires a full and exact description of at least oneform of the invention, such as that which follows, it is, of course, thepurpose of a patent to cover each new inventive concept therein nomatter how it may later be disguised by variations in form or additionsoi further improvements; and the appended claims are intended toaccomplish this W by particularly pointing'out the parts, improvements,or combinations in which the inventive concepts are found.

The meter chosen for illustration is a combined watt-hour integratingmeter and a maximum demand meter. The watt-hour meter element runs theintegrating register II. The demand meter unit controls the indicatingpointer II. This indicator is provided with a pusher lug 13 whichengages a maximum demand pointer It with which the present invention isprimarily concerned.

As seen in Fig. 1 the maximum demand pointer it has been pushed faralong the scale It by the indicator or pusher II, and the pusher hasbeen receded to a lower value indicating a decreased demand. Thus themaximum demand pointer It remains at the position of maximum demanduntil it is read by the meter reader at the end of a billing period andthen turned back to zero or to the momentary position of the indicatorII. It is evident that a very desirable characteristic for the meter isthat the maximum demand pointer has complete stability. In other words,it should remain dependably in any position'to which it is moved by theindicator it so that it will not be moved from this position byaccidental vibrations or by intentional jolting of the meter base I].

According to the present invention. this stability or dependableresistance to displacement is provided by the damping unit shown in Fig.2. In this figure, the maximum demand pointer it carries a bushing itwhich projects into a cup is but moves freely with respect theretoexcept insofar as relative movement is opposed by an intervening body ofgrease 2i. Of course, there is inevitably some bearing friction but thatis reduced as much as is practical and may be ignored for the purpose01' present considerations. The cup is is stationarily mounted. It may,for example. be staked to meter plate 22 which may be a part of theframe of the meter. Another cup 23 may desirably be provided. servingmainly as dust guard. In the illustrated form it is rigidly carried withthe pointer ll and bushing iii so as to rotate with them.

A bearing sleeve 24 is preferably provided for the rotating parts. Itmay be carried rigidly by the cup I! and, therefore, berigid with theframe member 22. It serves as a bearing for the pointer it andassociated rotating parts but has wide clearance around the indicatorshaft or meter preferably bein adiustablcby an adiustment devicell(omittedinfl8.2i

is probablv At the present fer-red. and the preferred grade is that soldas Stop Cock Grease by the Dow Corning Corporation of Midland, Michigan.This beenfoimdtomeetalloftherequirementsand its viscosity, which remainssubstantially constant throughout the temperature ranges commerciallyencountered seems to be ideal. The pointer adequately resistsdisplacement by vibration or jarrin although the srease seems to addsubstantially no esistance to movement or the pointer it at the slowspeeds at which it is moved by indicator or usher i2. course, it mustadd some resistance but it is well within the ermissible values. Thegrease shows no tendency to how out of place at the highat temperaturescommercially encountered. and the horizontal podtioning oi the shaft istherefore entirely sate. Likewise, at the highest temperaturescommercially encountered, the pointer II is adequately stabilizedagainst improper displacement. It should be noted that the pointer H isprovided with a counterweight 3i which preferably exactly balances itabout the axis of shaft 28.

Very little grease is required. It is not even necessary that thechamber between bushing ll andcup iflbeiilled. InFig.2,thepartshave beenshown greatly enlarged.

It would, of course, be very diflicult to permit free rotation of thepointer ll without also having some end play in its bearings. With ahorizontal axis, gravity has no tendency to eliminate this end play. Itmight have been supposed that such end play would cause a separation ofthe greasefromoneofthechamberwallsaudthat upon such separation its valueas a dampening agent would be destroyed. It has been found, however,that with such reasonable and play as would be consistent with goodinstrument practice, the grease will continue to cling to both the cupI! and the bushing i8 and will have suilicient cohesiveness to stretchout in an axial direction rather than to separate within itself. Anyother non-drying liquid having the indicated characteristics in thetemperature ran e indiacted as to viscosit adhesiveness.

an able andimmunityto chemicalchangeasusedoouidbeusedinplaceoithegrease.

Prom theforegoing it isseen thataninstrument indicator is providedtogether with a dmpeningdevicewhichissuitablei'orusewithahormontalaxisandwhichmaintains characteristics throughout a wide meat,but it satisfactorily and dependably stabilismtheindicatoragainstdisplacementbyvibration or jolts.

We claim:

1. A dampening unit for a member rotatable about a generally horizontalaxis including a surface associated with said member to rotatetherewith. a stationary surface facing thefirstgnamedsurfaceandspacertherefrommndabody com rising silicone greaseengagin both the said surlaces; the space between the surfaces occupiedby the viscous liquid opening'downwardlv wherebythegreasewouldbefrtoiiowfromthe chamberifitsviscositype ttedittoiiowby gravity, and saidgrease having viscosity characteristics, at all temperatures betweenapproximatew 250 1'. above 0 and F. below 0, preventing flow by gravityand causing no appreciinaccuracy in the pointer positioning.

2.'A dampening unit for a member rotatable about a generally horizontalaxis including a surface associated with said member to rotatetherewith, a statiomry surface facing the first-named suriace and spacedtherefrom, and a body comprising viscous liquid engaging both the saidsurfaces; the space between the surfaces occupied by the viscous liquidopening downwardly whereby the viscous liquid would be free to new from40 the chamber if its viscosity permitted it to flow by gravity, andsaid viscous liquid having viscosity characteristics; at alltemperatures between approximately 250 F. above 0 and 20 F. below 0,preventing flow by gravity and causing 5 no appreciable inaccuracy inthe pointer positioning.

3. A maximum demand meter including 'a pusher, a maximum demand pointerincluding a hub portion rotatably mounted about ahorisoaontalaxisanddisposedtobedrivenbythc pusher to a position ofmaximum demand and left there, and dampening means for resistingdisplacement of the pointer by vibration or mechanical shocks includinga stationary surface, a

surface spaced therefrom which rotates with the hub portion, the spacebetween said surfaces be ing open peripherally to a space larger thansaid first-named space, and a body comprising silicone stop cock greasebetween said surfaces and held in place by its viscosity but for whichit would be free to run out, said pointer and the parts moving therewithoutside of the bearing therefor being free from'contact with anystationary solid other than the grease.

s5 4. A maximum demand meter including a pusher, a maximum demandpointer including,

a hub portion rotatably mounted about ahoriaontalaxisanddisposedtobedrivenbythe pusher to a position of maximumdemand and left there, and dampening means, for resisting displacementor the pointer by vibration or mechanical Jars, cooperating with asurface associated with said pointer to rotate therewith, and includinga stationary surface facing the firstcohesiveness named surface andspaced therefrom and a body auspas comprising viscous liquid engagingboth the said surfaces, the space between the surfaces occupied by theviscous liquid opening downwardly whereby the viscous liquid would befree to now from the chamber if its viscosity permitted it to flow bygravity, and said viscous liquid having viscosity characteristics, atall temperatures between approximately 250 F. above 0 and 20 F. below 0,preventing flow by gravity and causing no appreciable inaccuracy in thepointer positioning.

5. A maximum demand meter including a pusher, a maximum demand pointerincluding a hub portion ro-tatably mounted about a hori zontal axis anddisposed to be driven by the pusher to a position of maximum demand andleft there, and dampening means, for resisting displacement of thepointer by vibration or mechanical jars, co-operating with a surfaceassociated with said pointer to rotate therewith, and

LOUIS A. PAINE. RICHARD A. ROAD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,114,691 Herz Oct. 20, 19141,166,719 Shebol et a1. Jan. 4, 1916 1,428,225 Fulton Sept. 5, 19221,461,091 Henley July 10, 1923 1,462,141 Leitch July 17, 1923 1,526,306Sprenger Feb. 10, 1925 2,149,374 Wellman Mar. '7, 1939 2,171,183 LambAug. 29, 1939 2,182,076 Elmer Dec. 5, 1939 OTHER REFERENCES Article fromNov. 1944 issue of Modern Plastics entitled SiliconesHigh PolymericSubstances," by S. L. Bass et a1.

Modern Plastics, Nov. 1944, pages 124, 125, 126, 212 and 214.

